Lubrication of totally enclosed mechanisms



June 4, 1963 TANNEN BERGER 3,091,917

LUBRICATION OF TOTALLY ENCLOSED MECHANISMS Filed June 20, 1960 m VE/V TOR HELM u TH TANAIE/VBERGER United States Patent 3,091,917 LUBRHCATEON 0F TUTALLY ENCLUSED MECHANISM Kielmuth Tannenherger, Geneva, Switzerland, assignor to linstitut Dr. lng. Reinhard Stranmann A.G., Waldenhnrg, Switzerland, a corporation of Switzerland Filed lune 20, 1960, Ser. No. 37,188 Claims priority, application Switzerland June 22, 1959 6 Claims. (Cl. 58-9tl) The present invention relates to the lubrication of totally enclosed mechanisms, and has for an object to provide an improved system of lubrication in which a lubricant substance is intermittently or continuously applied in the gaseous phase from a reservoir for forming an at least monomolecular lubricant film onsaid surf-aces. A method of this kind has already been described in the now abandoned applications Serial No. 782,235, filed December 22, 1958, and Serial No. 1,953 tiled January 512, 1960.

According to the present invention the lubricant reservoir consists of a material which has the effect of reducing the vapour pressure of the substance inside the reservoir to a level below the vapour pressure of the same substance outside the reservoir (but inside the casing) in such manner that droplets formed after evaporation can recondense in the reservoir. The reduction of vapour pressure inside the reservoir can be achieved by suitable choice of the material of which the reservoir is made, said material causing a reduction of the vapour pressure of the lubricant by adsorption, absorption, or expansion, i.e. swelling. However, the desired reduction of vapour pressure can be achieved by alternative means, fior instance by dissolving in the lubricant a substance which causes the solution to have avapour pressure below the vapour pressure of the lubricant.

The mechanism to which the invention is applied may be, for instance, a pocket or wrist watch, or some other instrument in which there are relatively moving parts having surfaces in frictional contact and contained within a sealed casing. For instance, in a watch it is proposed to provide a lubricant reservoir which consists of partly vulcanised rubber which is 50% saturated with say, heptane. When the casing is closed, a heptaneatmosphere will exist in the casing and and a heptane film will form on all surfaces. The reduction of vapour pressure due to the solution of rubber in the heptane inside the reservoir causes any condensation of hept-ane to occur principally in the reservoir, so that elsewhere in the watch no undesirable accumulations of liquid will form, or at least such accumulations cannot persist. It is important that the saturation of the reservoir should be less than 100%. It will be understood that heptane may be replaced by another liquid which is a suitable lubricant, such as for instance other hydrocarbons (e.g. pentane, hexane, octane, nonane, decane, undecane, dodecane, pentene, hexene, heptene, octene, benzene, toluene, xylene, nesitylene, tetramethy-l benzene, ethyl benzene, diethyl benzene, triethyl benzene, butyl benzene, anyl benzene, diamyl benzene, dibutyl benzene, methyl ethyl benzene, methyl butyl benzene, methyl propyl benzene, ethyl propyl benzene, ethyl butyl benzene, anyl naphthalene, cyclopentane, cyclohex-ane, cycloheptane, tetraline, decaline and pinene) hydrocarbon mixtures (such as kerosene, petroleum, terpenaline, lignonine, petroleum ether, gas oil, crude oil, diesel oil and paraifin oil), halides (such as n-propyl chloride, n-propyl bromide, n-propyl fluoride, n-butyl chloride, n butyl bromide, n bntyl fluoride, pentyl chloride, pentyl bromide, pentyl fluoride (=amyl fluoride), hexyl chloride, hexyl bromide, hexyl fluoride, heptyl chloride, heptyl bromide, heptyl fluoride,

3,9l,9l7. Patented June 4, 1953 2 dihalides, trihalides, tetrahalides, perchlorethylene, epichlorohydrine and chlorobenzene), aldehydes (such as oenanth'aldehvde, butynaldehyde), ketones (such as methyl-n-nonyl ketone), alcohols (such as bu-tanol, ethanol, namyl alcohol and benzyl alcohol), aliphatic acids (such as oenanthic acids), nitriles (such as propioni-trile, benzon-itnile), ethers (such as dibutyl ether, diamyl ether, dihexyl ether, methyl decyl ether), esters (such as amyl acetate, butyl acetate, butyl butyra-te, amyl butyrate, glycol difonmiate, propyl tormiate, hexyl acetate, ethyl acetate, dibutyl oxalate, diethyl onalate, tributyl borate, rtriethyl hereto and ethyl lactate), thioaldehydes (such as thiooenanthaldehyde, thiobutyraldehyde), thioalcohols (such as butyl mercaptan), th-ioethers (such as methyl decyl :thioether and diethyl sulphide), thiocyanates (such as ethyl thiocyanate), isothiocyanates (such as ethyl isothiocy-anate) as well as amyl, methyl and butyl Cellosolve, piperidine, propylene oxide, or carbon disulphide.

The reservoir can be made of any of a variety of mate rials of which the following are examples: silica gel; salts of monoor polvb asic long chain aliphatic acids with polyacid bases (such as aluminum stearate); mildly crosslinked and moderately expansible polymers, for instance one of the following: cellulose esters or ethers (e.g. nit-r0 or ace-tyl cellulose, cellulose propionate, cellulose acetate, cellulose butyrate, ethyl cellulose, benzyl cellulose); rubber (cg. slightly vulcanised, natural or synthetic rubbers, or the rubber known as super-Para rubber); acrylic or methacrylic resins; alkyd resins; coumarone resins, epoxide resins; furane resins; polyolefines; polyurethanes; melamine resins; phenolic resins; polyamides; polyesters; resorcinol resins; polvsulphides; silicones, and polyvinyl resins.

Alternative ways of reducing the vapour pressure in the lubricant reservoir can be used, for instance the solution in the lubricant of a substance (such as an expansible polymer or an organic substance of a lower molecular weight) which imparts to the solution a vapour pressure below the vapour pressure of the lubricant.

The invention will now be described by way of illustration only with reference to the accompanying drawing which is a view of a watertight Watch with the back of the casing removed.

In the drawing, a watertight casing it contains a watch movement 2. Between the movement 2 and the outer Wall in of the casing lis a reservoir 3 for the substance which is to act as the lubricant. This reservoir may consist or any one of the above-mentioned materials, for instance super-Para rubber, or of a mildly cross linked expansible polymer soaked in one of the previously mentioned liquids, for instance a hydrocarbon, such as octane, but not fully saturated.

All the components of the watch movement 2 are first well cleaned but are neither oiled nor greased. When the casing l is closed as by screwing on the back (not shown), an atmosphere of octane vapour will form inside the casing 1 causing the molecules of octane to be depos ited on every surface of the movement 2 and to form a thin film of octane thereon. Experiments have disclosed that this method of lubricating a watch is superior to the conventional method because all the parts of the watch are thereby equally lubricated, both when the Watch is new and after a considerable period of use, so that the loss in energy due to friction is less than in a watch which has been lubricated in the conventional manner with anormal Watch oil.

Further tests showed that the coeflicient of friction between an arbor consisting of an alloy based on Ni and a sapphire was, in order of magnitude, between 0.06 and 0.20 which is sufficient to ensure satisfactory functioning of the watch. The experiments further show that rapid 3 cooling may cause condensed droplets to form in the watch, but that these will quickly disappear without Warning because the Vapour pressure of the lubricant contained in the reservoir is lower than the vapour pressure of the droplets of the substance forming outside the reservoir.

The invention is not limited in its application to watches. The mechanism 2 which is contained in the casing 1 may be any kind of instrument or apparatus comprising appropriately small parts.

I claim:

1. Means for lubricating members in an enclosed housing comprising:

(a) a lubricant in said housing;

(b) a reservoir within said housing;

(c) said lubricant being normally in the vapor state, and being free to pass between said reservoir and said members for lubrication of said members; and

'(d) said reservoir being made of a substance adapted to coact with said lubricant to impart to said lubricant a reduced vapor pressure in said reservoir whereby to prevent accumulations of excess liquid lubricant outside said reservoir.

2. Means for lubricating members in an enclosed hous ing as defined in claim 1 wherein said substance of said reservoir is adapted to reduce the vapor pressure of said lubricant by adsorption.

3. Means for lubricating members in an enclosed housing as defined in claim 1 wherein said substance of said reservoir is adapted to reduce the vapor pressure of said lubricant by absorption.

4. Means for lubricating members in an enclosed hous ing as defined in claim 1 wherein said substance of said reservoir is adapted to reduce the vapor pressure of said lubricant by expansion.

5. Means for lubricating members in an enclosed housing as defined in claim 1 wherein said substance of said reservoir is soluble in said lubricant so as to impart to said lubricant a reduced vapor pressure in said reservoir.

6. A watertight watch comp-rising:

(a) a watch movement;

(b) a Watertight casing enclosing said movement;

(0) a lubricant in said casing;

(d) a reservoir within said casing surrounding said movement; and,

(e) said reservoir being made of a substance soluble in said lubricant so as to impart to said lubricant a reduced vapor pressure in said reservoir.

References Cited in the file of this patent Mmf- 

1. MEANS FOR LUBRICATING MEMBERS IN AN ENCLOSED HOUSING COMPRISING: (A) A LUBRICANT IN SAID HOUSING; (B) A RESERVOIR WITHIN SAID HOUSING; (C) SAID LUBRICANT BEING NORMALLY IN THE VAPOR STATE, AND BEING FREE TO PASS BETWEEN SAID RESERVOIR AND SAID MEMBERS FOR LUBRICATION OF SAID MEMBERS; AND (D) SAID RESERVOIR BEING MADE OF A SUBSTANCE ADAPTED TO COACT WITH SAID LUBRICANT TO IMPART TO SAID LUBRICANT A REDUCED VAPOR PRESSURE IN SAID RESERVOIR WHEREBY TO PREVENT ACCUMULATIONS OF EXCESS LIQUID LUBRICANT OUTSIDE SAID RESERVOIR. 